Hi all,
I'm running kudu 1.6.0-cdh5.14.2. When looking into the logs of tablet server,
I find most of the compactions are compacting small files (~40MB for each). For
example:
I0615 07:22:42.63735130614tablet.cc:1661] T 6bdefb8c27764a0597dcf98ee1b450ba P
70f3e54fe0f3490cbf0371a6830a33a7: Compaction: stage 1 complete, picked 4
rowsets to compact
I0615 07:22:42.63738530614compaction.cc:903] Selected 4 rowsets to compact:
I0615 07:22:42.63739330614compaction.cc:906] RowSet(343)(current size on disk:
~40666600 bytes)
I0615 07:22:42.63740130614compaction.cc:906] RowSet(1563)(current size on disk:
~34720852 bytes)
I0615 07:22:42.63740830614compaction.cc:906] RowSet(1645)(current size on disk:
~29914833 bytes)
I0615 07:22:42.63741530614compaction.cc:906] RowSet(1870)(current size on disk:
~29007249 bytes)
I0615 07:22:42.63742830614tablet.cc:1447] T 6bdefb8c27764a0597dcf98ee1b450ba P
70f3e54fe0f3490cbf0371a6830a33a7: Compaction: entering phase 1 (flushing
snapshot). Phase 1 snapshot: MvccSnapshot[committed={T|T < 6263071556616208384
or (T in {6263071556616208384})}]
I0615 07:22:42.64158230614multi_column_writer.cc:103] Opened CFile writers for
124 column(s)
I0615 07:22:43.87539630614multi_column_writer.cc:103] Opened CFile writers for
124 column(s)
I0615 07:22:44.41842130614multi_column_writer.cc:103] Opened CFile writers for
124 column(s)
I0615 07:22:45.11438930614multi_column_writer.cc:103] Opened CFile writers for
124 column(s)
I0615 07:22:54.76256330614tablet.cc:1532] T 6bdefb8c27764a0597dcf98ee1b450ba P
70f3e54fe0f3490cbf0371a6830a33a7: Compaction: entering phase 2 (starting to
duplicate updates in new rowsets)
I0615 07:22:54.77357230614tablet.cc:1587] T 6bdefb8c27764a0597dcf98ee1b450ba P
70f3e54fe0f3490cbf0371a6830a33a7: Compaction Phase 2: carrying over any updates
which arrived during Phase 1
I0615 07:22:54.77359930614tablet.cc:1589] T 6bdefb8c27764a0597dcf98ee1b450ba P
70f3e54fe0f3490cbf0371a6830a33a7: Phase 2 snapshot: MvccSnapshot[committed={T|T
< 6263071556616208384 or (T in {6263071556616208384})}]
I0615 07:22:55.18975730614tablet.cc:1631] T 6bdefb8c27764a0597dcf98ee1b450ba P
70f3e54fe0f3490cbf0371a6830a33a7: Compaction successful on 82987 rows
(123387929 bytes)
I0615 07:22:55.19142630614maintenance_manager.cc:491] Time spent running
CompactRowSetsOp(6bdefb8c27764a0597dcf98ee1b450ba): real 12.628suser 1.460ssys
0.410s
I0615 07:22:55.19148430614maintenance_manager.cc:497] P
70f3e54fe0f3490cbf0371a6830a33a7:
CompactRowSetsOp(6bdefb8c27764a0597dcf98ee1b450ba) metrics:
{"cfile_cache_hit":812,"cfile_cache_hit_bytes":16840376,"cfile_cache_miss":2730,"cfile_cache_miss_bytes":251298442,"cfile_init":496,"data
dirs.queue_time_us":6646,"data dirs.run_cpu_time_us":2188,"data
dirs.run_wall_time_us":101717,"fdatasync":315,"fdatasync_us":9617174,"lbm_read_time_us":1288971,"lbm_reads_1-10_ms":32,"lbm_reads_10-100_ms":41,"lbm_reads_lt_1ms":4641,"lbm_write_time_us":122520,"lbm_writes_lt_1ms":2799,"mutex_wait_us":25,"spinlock_wait_cycles":155264,"tcmalloc_contention_cycles":768,"thread_start_us":677,"threads_started":14,"wal-append.queue_time_us":300}
The flush_threshold_mb is set in the default value (1024). Wouldn't the flushed
file size be ~1GB?
I think increasing the initial RowSet size can reduce compactions and then
reduce the impact of other ongoing operations. It may also improve the flush
performance. Is that right? If so, how can I increase the RowSet size?
I'd be grateful if someone can make me clear about these!
Thanks,
Quanlong
